Thread cutting machine



Oct. 17, 1939.

' J. LUPO. IR

THREAD CUTTING MACHINE Filed April 28, 1957 4 Sheets-Sheet 1 I N VEN TOR. Jauvw [0 0 ATTORNEYS Oct. 17, 1939. J. LUPO. JR- 2,176,676

THREAD CUTTING MACHINE Filed April 28,, 1957 4 Sheets-Sheet 2 R S; INVENTOR.

" JOSEPH 10, 0, JR.

ATTORNEYS v Oct.'17, 1939. J. LUPO. JR 2,176,676 I THREAD CUTTING MACHINE Filed April 28, 1937 4 Sheets-Sheet 4 INVENTOR. JOJ'EPH [(1/ 0 e/i.

ATTORNEYS Patented Oct. 17, 1939 arrears metre a charms me I Joseph lLnpo, n), Bronx, N12. Y 4 Application April 28, 1937, semi No. 11391419 4 Claims. (cl. ill-d) This invention relates to a thread cutting'machine which is especially designed for cutting either internal or external threads in articles made of synthetic resin or other synthetic plast tics, although the same may be utilized on soft alloy metals, such as aluminum, copper, brass or r the like.

Broadly,- the invention comprehends an improved thread cutting machine which is so con- 0 structed and arranged as to eflectually and clean- L 'ly'cut threads at a high rate of speed without gumming or chipping, ripping, burning or otherwise marring the stock being cut.

I As a further feature the invention provides a cutting operation, is automatically moved out of contact with the stock and withdrawn to retracted position to aiford a' clearance for the dll manual removal of the threaded stock and the emplacement of a new piece of stock in the machine.

Other objects of the invention are to provide a machine of the indicated character which is not unduly complicated in its construtztiomwhich is extremely simple'ln'its mode of operation and which is highly emcient for itslintended purpose.

With the aboveenumerated and other objects in view, referenceis now made to the following specification and theaccompanying drawings in which there is disclosed,- by way of example, a preferred embodiment of the invention, while the claims are intended to cover variations and modifications which fall within the scope of the invention.

In the drawings: l

-Fig. 1 is a top plan view of a threading machine constructed in accordance with the invention.

' Fig. 2 is alongitudinal sectional view taken approximately on the line 2-2 of Fig. 1.

Fig. 3 is a transverse sectional view taken approximately 0n the line 3--3 of Fig. 1.

' Fig. 4 is a similar view taken approximately on 66 the line L-d of Fig. 1 V, p f

machine which is readily adjustable to vary the Fig. 5 is a diagrammatic view on a larger scale;

illustrating the various positions of the cutter with reference to the stock when cutting a thread on the inner periphery thereof. 1

Fig. 6 is a similar view illustratingthe relative 5 positions of the cutter to the stock when cutting a thread on the exterior periphery of the stock.

Referring to the drawings by characters of eference, it designates the base or table of the machine which is preferably supported in elevated,

relation to the floor by legs ii and which has secured in Jfixed relation thereon. adjacent one side and near the front thereof, a bracket i2 havingsuper-posed aligned bearings it and it.

A hollowtcylindrical sleeve i5 is journaled in the alignedhearings l3 and it for rotation and is provided at its inner end with an enlarged head It having an inwardly flared or frusto-conical chuck engaging face ii. A pulley it for rotating the sleeve has its hub it surrounding the sleeve 05 and secured: thereto by a set screw 20, the hub l9 and head it being disposed on opposite sides ofthe bearing M to prevent'axial movenintof the'sleeve while permitting rotation'thereof; 4 '2 --A stock supporting chuck 2i of the split resilient typeis mounted for axial movement with reference to the sleeve l5 and is provided with a frusto-conical boss 22 adapted when moved .calchuck-engaging facei? to eiiect an inward radial contraction and gripping of the stock S and is adapted to inherently expand radially out- :ward when moved inwardly so as to release the stocks; Theouter end portion 23 of the chuck is detachablyassociated with a shaft 2d extending axially through the sleeveit and carrying ad- ,"jacent'its outerend a collar 25 adjustablyre tained in place thereon by a nut 26. Thesleeve,

adjacent its inner end, is provided withan in- 'ternal annular shoulder 21 constituting a spring seat against which is'seated one end of a coiled expansion-spring 28 which surrounds the shaft 24 and which engages at its outer end with the collar 25." This functions to normally efiect an.

outward movement and inward radial contrac--- 'tion of the chuck 2| to grip and retain the stock S.

after its emplacement therein.

In order to provide means for manually shifting the shaft 24 and chuck 2i inwardly against the action of' the spring to releaseone piece of stock and insert a new piece, a lever 29 is fulcrumed as at 30 for swinging movement of its upper end 3| into engagement with the outer end of the shaft 24 and suitable foot operated means 32 is conoutwardly into engagement with the frusto-coni- 2 v nected with the lower end of said lever for actuating the same.

- A driven rotary disk-like thread cutting tool 35. having its axis of rotation disposed in a line parallel with the line of the axis of rotation of the stock holder or chuck 2| is mounted for axial movement across'the periphery of the stock. 7 As illustrated, the tool is detachably associated with a drive shaft mounted for rotation in a tubular housing 31 which housing is axially slidable in spaced aligned bearings 33 and 33 secured to and projecting upwardly from a carriage 45. The

carriage is movable laterally and in a direction perpendicular to the axis of rotation of the tool on spaced guide cleats 4| and 42 fixed to the base or table l0 near the front thereof and adjacent the side opposite that where the bracket I2 is located.

The outer end 43 of the shaft 35 protrudes beyond thehousing and has secured thereto a pulley 44' around which is trained a belt 45 for rotating the shaft 35 and tool 35 at a high rate of speed, approximately 4000 R. P. M. v

The tool is. fedacross theperiphery of the stock S by means'of a worm feed wheel 43 which is secured to a worm shaft 41 journaled for rotation in the upper ends of a pair of spaced bearing arms 43 which arms are secured at their lower ends to a rock shaft 43 Journaled in upstanding bearings on the carriage 43 adjacent the rearthereof. t

A worm finger 5| is mounted for limited axial sliding movement in a tubular boss 52 which projects radially from a collar 53 arranged in surrounding relation to and upon the tubular housing 31 and secured thereon against axial movement by a set screw 54, the collar 53 .being located on the tubular housing between the bearings 33 and 39. Acoiled expansion spring 55 surrounds the housing 31 and is interposed between the bearing ,33 and the collar 53 to exert a tension for nor cam 55 which engages a cam roller 51 on a bifurcarriage 40 in spaced yokes 13.

cated lift bar 55 which has pivoted as at 59 to its upper end, a thrust rod 53 extending through a yoke 5| on one of the bearing arms 43. The cam 55 is secured to a cam shaft 52 which is journaled for rotation in bearings 53 and 54 secured to the rear of the guide cleats 4| and 42. The cam shaft has also secured thereto a pair of cams 55 and 66 which are adapted to be selectively employed for controlling the transverse movement of the carriage 40, their selective use being dependent upon whether or not the thread is being cut in the outer or inner periphery of the stock S;

A cam roller 51 is journaled for rotation in bearing ears 58 depending from the rear end of thrust bar 69 located transversely beneath the The thrust bar 53 is formed with a threaded longitudinally extending bore 1| engaged by a jack screw 12 which protrudes forwardly from and is swiveled to the carriage and provided at its forward end with a manipulating knob 13 by virtue of which relative adjustment of the carriage 40 with reference to the thrust bar 53 and cam wheel 51 may be effected. Coiled contractile springs 14 are attached to the rear of the carriage 40 and to rearwardly spaced anchoring pins 15 fixed to and upstanding from the base or tablel0 adjacent the rear ,thereof.

The'stock holder or chuck 2| is rotated at approximately 60 R. P. M. by means of a belt trained around the pulley l8 and around a pulley II on a countershaft 82 which is turned by means of a pulley 83 secured thereto and around which abelt I4 is trained leading from a suitable prime gearing in a gear box 85 which may, as illustrated,

, be operated from the sleeve l5 through a pulley and belt drive 85 and 31. In order to compensate for the rocking movement of the worm feed shaft 41, a flexible or universal joint 88 is interposed between the worm feed shaft 41 and the drive shaft 33 from the gearing in the gear box 85.

In use and operation of the machine, the tool 35, the chuck 2| and the cam and warm feed shafts 62 and 41 are continuously driven. The operator standing in front of the machine inserts the p. ace of stock 8 to be threaded in the chuck 2| when the same is expanded by swinging the upper end 3| of the lever 29 to the right, by depressing the foot operated means 32. .The piece of stock S is inserted while the chuck 2| is rotating thereby facilitating proper centering and positioning of the stock therein. This is accomplished while the tool 35 is in the retracted position, shown in Figs. 1 and 2 of the drawings and immediately following the emplacement of the piece of stock in the chuck, the foot operated means 32 is released so that the spring 28 functions to shift the shaft 24 to the left to draw the frusto-conical .boss 22 into contact with the frusto-conical chuck engaging face l1 to grip the stock for rotation with the chuck.

In the present illustration, the machine is set and illustrated for cuting an internal thread in the stock S. With the tool 35 in the retracted position illustrated in Fig. 1, immediately follow ing the emplacement and gripping of the stock in the chuck 2|, the cam 56 acting on the lift bar 53 rocks the bearing arms 48 to engage the worm wheel 45 with the worm finger 5|. This feeds the tool 35 to the left across the inner periphery of the stock 8, the combined translatory move-- ment and rotation of the tool cutting a spiral groove or thread in the inner periphery of the stock. When the tool has completed the cutting 'of the thread in the stock, the cam 65 is so timed in its rotation as to shift the carriage 40 forwardly to thereby move the tool radially inward with reference to the stock to disengage its cutting edge from the stockperiphery. Immediately following this, the cam 56 again actuates the lift bar 58 to swing or rock the worm feed wheel 48 to a position out of engagement with the cam finger 5|. Upon disengagement of the worm wheel from the cam finger, the spring 55, acting upon the collar 53 shifts the tubular housing 31 and the tool 35 to the'retracted position being arrested in its movement by the abutment of the collar 53' with the bearing 39, while the cal'n,65 permits the springs 14 to move the carriage rearwardly for a repetition of the cycle of operation.

It will be understood that immediately upon retraction of the tool,'the operator removes the piece of stock which has been threaded and inserts a. new piece of stock. Obviously, the tool 35 employed may be of any desired cross sectional shape to out either av-shaped thread as shown or any other shape desired, and within the scope of the invention the tool may be so shaped as to cut a multiple thread while the pitch of the thread may be varied by interchanging the worm wheel with others having different degrees of pitch. Also it is apparent that by turningv the manipulating knob I3, the depth of the thread may be varied while the screw 12 is employed for initiallysetting the machine for the cutting operation. The cam 86 may be selectively brought into an active position with the cam roller 6'?! and the cam 65 moved to an whenthe machine is employed for cutting threads on the external periphery of the stock as it is found in practice that a greater extent oi movement of the carriage is desirable when the threads are externally cut.

In Fig. f the drawings, the relative positions or the cutter 35 with reference to the stock S are illustrated, the position a showing the cutter in full lines in a position whereby upon amai movement in the direction indicated by the arrow the same will move across the inner periphery of the stock which is likewise rotating until it reaches the position b shown in dotted lines, this movement of the cutter being efi'ected by the interengagement of the worm finger 5i with the worm BE.

After completion of the cutting of the desired number of convolutions of the thread, the cutter 35 is moved from the position b to the position 0 radially inward with reference to the stock and this movement is controlled by the cam 55 which effects the forward shifting or sliding movement of the carriage ti). It will be, of course, understood that the extent of the movement from the position a to the position b, while the cutter is in cutting engagement with the stock, is controlled by the length of time the low portion of the cam face engages with the cam roller 6'5. From the position 0 the tool (I and this is accomplished by means of the spring 55 as soon as the cam 5t operates to swing the worm wheel :36 out of engagement with the worm finger 56. From the position 6, the tool 35 is moved again to the position a by means of the springs it acting upon the carriage it, shifting the same rearwardly as controlled by the face of the cam 65 and the cam roller M. This places the tool in an axial line where, upon reengagement of the worm wheel 46 with the worm finger, the tool will be again moved from the position a to the position b repeating the operation.

Immediately following the retraction of the tool from the position 0 to the position d, it will be understood that the operator releases the chuck,

removes the stock and inserts a new piece of stock for the threading operation.

In Fig. 6, the various positions of the toolduring its cycle of movement, is illustrated where the machine is employed for cutting an outside thread. 'The only diil'erence in this use is that.

from the position b to the position 0, the tool is moved radially outward with reference to the stock and after retraction is moved radially inwardwith reference to the stock from the position 11 to the position a. In this instance, the cam 65 is moved out of position and the cam. is moved into position for contact with the cam roller 61, the cam having a face which imparts to the carriage 40 a greater movement as it is immaterial how far away from the outer periphinactive position 3'5 is retracted tothe position ery the stock is moved to the when cutting internal threads, the radial inward movement is necessarily limited particularly where the threads are being cut on a piece ofstock having a limited internal diameter.

What is claimed is: 1. In a thread cutting machine, a base, a continuously driven rotary stock holder having a' thread cutting tool having its axis of rotation disposed in a hne parallel with the line of the axis of rotation of the stock holder, a non-rotary support for said tool slidably mounted on said carriage for moving the tool axially, interengageable means including a continuously driven worm and a worm engaging finger provided respectively on the carriage and tool support for feeding the tool across the periphery of the stock, interchgageable cam means on-the base and carriage for efiectlng lateral movement of the carriage to engage and disengage the tool with the periphery of the stock, cam means for engaging and disengaging the worm and worm engaging finger, and spring means for retracting the tool support when the worm and worm engaging finger are disengaged.

2. In a thread cutting machine, a base, a continuously driven. rotary stock holder having a position cwhereas,

fixed relation on said base, a carriage guidedly mounted on said base for lateral movement perpendicular to the axis of rotation of the stock and stock holder, a continuously driven rotary thread cutting tool having its axis of rotation disposed in a line parallel with the line of the axis of rotation of the stock holder, a non-rotary support for said tool slidablymounted on said carriage for moving the tool axially, interengageable radial movement of the tool with reference thereto, means for adjusting the carriage with reference to the cam means to initially position the tool with reference to the stock and to vary the depth of the thread to be cut, cam means for engaging and disengaging the worm and worm engaging finger, and spring means for retracting the tool support and tool when the worm and worm engaging finger are disengaged.

3. In a thread cutting machine, a continuously driven rotary stock holder normally fixed against axial movement and having manually releasable means for normally gripping the stock, a continuously driven rotary thread cutting tool, a non-rotary supporting sleeve for said tool, a carriage for said tool supporting sleeve having bearings'in which said sleeve is mounted for axial sliding movement, said .carriage being mounted for movement perpendicular to the axis of the tool and its supporting sleeve, interengageable means on the tool supporting sleeve and on the carriage comprising a worm and worm finger for feeding the tool across the periphery of the rotating stock and in thread cutting engagement therewith, cam means for moving the carriage perpendicular to the axis of the tool support to engage the tool with and disengage the same from the peripheryof the stock, cam means operable HIM to engage and disengage said worm and worm engaging finger, and spring means surrounding the tool supporting sleeve and adapted to retract said sleeve and tool when the worm finger is disengaged from the worm.

4. In a threadv cutting machine, a continuously driven rotary stock holder normally fixed against axial movement and having manually releasable means for normally gripping the stock, a vcon-- tinuously driven rotary thread cuttingtool, a non-rotary supporting sleeve for said tool, a carriage'ior said tool supporting sleeve having bearings in which said sleeve is mounted for axial sliding movement, said carriage being mounted for movement perpendicular to the axis of the tool and its supporting sleeve, interengageable means on the tool supporting sleeve and on the carriage comprising a worm and worm finger for feeding the tool across the periphery of the ratating stock and in thread cutting engagement therewith, one means for moving the carriage perpendicular to the axis of the tool support to engage the tool with and disengage the same from the periphery of the stock comprising a cam roller on the carriage ,adjustable with reference thereto, a fixed driven cam engageable with the roller, spring means for urging the carriage in a direction to engage the cam roller therewith,

a second cam on said cam shaft operable to en- 

